If you want to take a quick look at data, displaying it on the DMS or
SPARCstation, but not collecting header information or copying the data
to disk on the system computer, do a glance exposure:

ICL> glance red 5

In this example, a 5-second exposure is made on the Red channel and the data
appear in the DMS.
The data can then be inspected using on the DMS display before proceeding
further.

If you decide you want to keep this data on the system computer after all,
type

ICL> keep red <observation type> "

This command will assign a run number, collect headers and write the data to
a disk file in RUN_FILES a for a normal run.
The parameter observation type can take values from the set TARGET, SKY,
ARC, FLAT, DARK, BIAS, FLASH and MAP; the value of the parameter is written to
the FITS descriptor OBSTYPE.
If you have changed the instrumental set-up between taking the glance
exposure and saving it, the FITS header won't match the image.
Keep can save data from any type of observation
(not just from glance), so is
useful for rescuing data if a routine run does not complete correctly.

To make an observation that you do not intend to archive, but which you want to
save to disk on the system computer, use the scratch command.

ICL> scratch red 1 <observation type> <exposure time> "

causes the data (image plus headers) to be written to a `scratch file' S1.SDF
in the directory SCRATCH_FILES.
Scratch files have headers but aren't allocated run numbers; they are temporary
files that should not be exported from ING. The command wink
is equivalent
to scratch but does not collect FITS headers.

Any number of scratch files may be created (subject to disk-space
constraints) by substituting another file number for the 1 in the command.
If you make a scratch exposure into an existing scratch file, the new data
over-writes the old.

SCRATCH_FILES is initially the same directory as RUN_FILES but this can be
changed by redefining the logical name at job level and in user
mode.

If you later find that you want to keep a scratch file, you can convert it
to a proper run using the promote command.

ICL> promote 1

causes scratch file 1 to be allocated a run number and copied to RUN_FILES.